This invention deals with heating systems and more particularly with a solar boiler, utilizing as a collector discreet mirror sections that reflect rays to a central metal disc.
Heating systems can be classified in two ways: the space heaters and the central heaters. Fireplaces and electric resistance heaters fall into the first category. Each heats the air directly and thus usually serves only individual areas. Central heat systems manufacture heat in one of several kinds of furnaces, then distribute it to all parts of the house via a heat-conveying network of pipes or ducts. These are often described by naming both fuel and heat-carrying medium in the system (e.g., gas/warm air, oil/hot water, coal/steam, or any other interchangeable combination of these fuel and media). In some instances, a system may have acquired a special name, such as SOLAR HEAT although it could also be technically described by the fuel/generic name as well.
Solar energy comes from the heat produced by the rays of the sun as they strike the earth. The energy is used in many ways, the most important of which is heat, insofar as the homeowner is concerned. It is conceivable that the heat from the sun could provide a house with its entire heat requirements. Several factors affect total solar-energy utilization.
Primary among these is cost. Even though solar heat is free, methods of collecting and using that heat are relatively expensive as well as technically difficult. For example, recent analysis of costs produce the following figures:
Solar heating generally requires a collector equal in square footage to one-half the square feet of the house. Thus, a house with 1,000 square feet of living space would require 500 square feet of heat-collector area. With a good-performance heat collector running about ten dollars a square foot, the collector cost reaches about five thousand dollars.
The greatest technological problems are due to the fluctuations in the direction of the sun from season to season and the fact that it shines for only part of the 24-hour day and not at all on cloudy days.
The most difficult problem in adapting an existing home to solar energy use (often called retrofitting) is orientation. When a house has its roof edge running east and west and when the house has a double-pitch roof, it is possible to convert the southern roof exposure into a solar-energy collector.
A solar-heating system requires three basic elements. First is the collector, which absorbs the heat from the sun rays. The second is a method of storing the heat, against those periods when the sun is not shining on the collector. The third is the distribution system that carries the heat to where it is needed.
Although some conventional collectors are highly sophisticated in design and materials, the basic materials and methods are simple. The first requirement is a black plate that absorbs the heat from the sun. To this plate are fastened tubes through which the liquid being heated flows. (The liquid is what carries the heat from the collector). Ideally, the plate and tubes should be of a material that is an excellent heat conductor. All connections should be soldered to provide the efficiency of continuous metal conductance. However, adequate collectors have been built with aluminum plates and plastic. In this case, the connections are made with wire binding.
The arrangement of the tubing on the plate is determined by the total situation and most particularly by the method to be used for moving the liquid through the tubes. Ordinary convection is effective with some arrangements. It is more efficient and less limiting, however, if a pump moves the liquid.
The most common storage unit for solar systems using water is a tank of water. The system is set up so that water circulates through the heat collector and back into the storage tank, which gradually increases in temperature until it represents a huge supply of heated water. It is then moved through the heating system as required.
Some solar-energy systems circulate air through the system, instead of water. When this is the case, the storage unit is in the form of a large "crib" of concrete or concrete blocks, filled with fist-size rocks that have been rinsed and dried. The air heats these rocks.
When air is used in a solar-heating system, it is delivered through regular warm-air ducts, most efficiently with insulation on the ducts where they pass non-heated areas. Water systems, however, do not provide the best results if an attempt is made to utilize standard baseboard units and other hot water registers. The reason is that such units require water as hot as 140 degrees F., a temperature nearly impossible to achieve with conventional solar-heat collectors. Instead, heat exchangers are used with air systems, since they will extract heat from the air even though the temperature is as low as 100 degrees F.
Air collectors are considered best if heating is the only purpose of the system. Air from the collector or from storage travels through ducts the same as warm air from a furnace. The system can be engineered so that the sun provides the heat up to the limit of its capability and then the regular heating system adds whatever is necessary. Since air no hotter than 75 degrees F. will provide heating, the air system puts less demand on the collector.
Water systems on the other hand can be used for heating, for domestic water supply, bathing, etc. The pipes that carry the water are small and can often be installed in situations where warm-air ducts would be impossible. The power required to move the water through the pipes is much less than required to blow air through ducts. Hot water functions more efficiently in a heat exchanger than hot air. Meanwhile, as mentioned earlier, water must be hotter than air to provide an equivalent amount of residential heat.
The solar boiler utilizes heat produced by the rays of the sun as they strike its collector (discreet mirror sections that reflect sun rays to a central metal disc which can reach 750 degrees F.). It can be used to heat a structure utilizing a distribution system that forces the heat via a fan to where it is needed and to do steam welding and even air conditioning with steam pressure of 18 pounds. Depending upon the size and number of discreet mirror sections, the available heat can exceed 2,000 degrees F. Maximum efficiency of the solar boiler is achieved by two tracking systems, powered by solar cells that together allow the collector to follow the sun's path from sunrise to sunset and adjust for seasonal changes.